Statistical tests

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1 Task

Note

Find the solution here later.

1.1 Get started

We will again use the penguins data included in R.

As always, before you get started with the exercise, make sure that you load the tidyverse

library(tidyverse)

1.2 Compare the flipper length of penguins using statistical tests

Question: Does the mean flipper length differ between the 3 penguin species?

Do separate comparisons for

• Gentoo vs. Adelie
• Gentoo vs. Chinstrap
• Adelie vs. Chinstrap

Before you start, create a subset of each species as a vector.

For this, you can use the $ operator:

adelie <- filter(penguins, species == "Adelie")$flipper_len
chinstrap <- filter(penguins, species == "Chinstrap")$flipper_len
gentoo <- filter(penguins, species == "Gentoo")$flipper_len

Follow the decision tree for statistical tests:

1.3 Extra

Create a plot to show the results of your tests. Choose one of the following:

• Create a boxplot with notches to visually compare differences in flipper length between species
• Make a plot showing the mean and standard error of the mean as pointrange or point with errorbars

Add a geom_signif() layer to the plot you just created to indicate your test results